How do you know when your teen is telling you the truth? For many parents, being able to decipher truth from fiction in their kids is incredibly important. After studying human lie-detection and then implementing the principles while working with thousands of teens, parents and families, I wanted to point out a few patterns for adults, teachers and parents.The clues below are some of the statistical signs of deceit—meaning they most often show up in people who are lying. These are the common ones I have found working with teenagers. Although these are strong indicators of deceit, one clue alone does not guarantee lying—if you recognize some of the evidence below it is a red flag to get more information.1. Verbal NuanceIf the timing is off between gestures and words, lying or hidden emotions are most likely lurking. For example, if your teenager is talking about how angry they are about something, but their facial expression is one of sadness or neutrality, they are most likely forcing the emotion even though they do not feel it. Verbal nuance can also show up as a delayed reaction to the emotion. They might say, “Yeah, I am angry about it,” pause and then display an angry expression. This is not genuine emotion because their words are not matching their expressions.2. ReliefA liar almost always shows great relief when the subject is changed. If you are talking to your teen about an issue you are suspicious of and then move on from the topic, notice their reaction. If they show great relief or a total change in behavior, they were most likely tense or hiding something.3. Fear vs. SurpriseIn my presentations and articles on Social and Emotional Intelligence I often reference microexpressions. A microexpression is a brief, involuntary facial expression that is shown on the face of humans according to the emotions that are being experienced. Unlike regular pro-longed facial expressions, it is difficult to fake a microexpression. They often occur as fast as 1/15 to 1/25 of a second. There are seven universal microexpressions: disgust, anger, fear, sadness, happiness, surprise, and contempt. In terms of lying, I believe that fear and surprise are the most important ones for parents to recognize. After all, if you ask your teen, “Did you know about the cheating incident at school?” A fearful microexpression will tell you something very different than if they look surprised.

Surprise:

-The brows are raised and curved

-Skin below the brow is stretched

-Horizontal wrinkles across the forehead

-Eyelids are opened, white of the eye showing above and below

-Jaw drops open and teeth are parted but there is not tension or stretching of the mouth

Fear:

-Brows are raised and drawn together, usually in a flat line

-Wrinkles in the forehead are in the center between the brows, not across

-Upper eyelid is raised, but the lower lid is tense and drawn up

-Upper eye has white showing, but not the lower white

-Mouth is open and lips are slightly tensed or stretched and drawn back

4. Teenage Lying and Body LanguageThere are a few indicators of deceit demonstrated in body language. Liars typically show less physical expression and movement or are stiff and mechanical in movement (only true if your teenager is not expressive or full of movement normally). If they are lying their hand may go up to his or her face or throat, especially to the mouth. People often turn their body away from the adult or person they are lying to.5. Verbal CluesIf you are speaking with your teen and they begin responding to an accusation by offering a belief in general instead of the specific instance (i.e. Do you smoke pot? -I believe pot is dangerous) they are subconsciously avoiding answering the question. They also might add in additional details until you believe them to fill silences. Liars often use phrases like "To tell you the truth," "To be perfectly honest," and "Why would I lie to you?" Another clue to deceit is when teenagers have answers that sound extremely rehearsed even if it is about a casual event.Lying is a very natural, yet dangerous occurrence. Unfortunately it is part of growing up, but parents need to be aware of teens lying habits to keep them safe. I share these tips and hope they will be used in the right circumstance.

About The Author:

Vanessa Van Petten is one of the nation's youngest experts, or 'youthologists' on parenting and adolescents. She now runs her popular parenting website, RadicalParenting.com, which she writes with 120 other teenage writers to answer questions from parents and adults. Her approach has been featured by CNN, Fox News, and Wall Street Journal. She was also on the Real Housewives of Orange County helping the housewives with troubled teens. Her next book, "Do I Get My Allowance Before or After I'm Grounded?" is being released in September 2011 with Plume Books of Penguin USA.